Al/Ti Synergistic Doping Enhanced Cycle Stability of Li‐Rich Layered Oxides

Abstract Li‐rich layered oxides (LLOs) suffer from rapid voltage decay and capacity fading, greatly hindering their applications as high‐energy cathode materials for Li‐ion batteries (LIBs), which are closely associated with irreversible structural transformation and lattice oxygen loss upon electrochemical cycling. A strategy of Al/Ti synergistic bulk doping is proposed to stabilize LLOs against structural degradations, yielding remarkable electrochemical performance including a minor voltage decay of 0.34 mV cycle−1 and a superior capacity retention of 89.7% over 500 cycles at 1C. The improved structural stability of Al/Ti codoped LLOs is well maintained after not only initial but also long cycles. This effect can be attributed to the cooperation of Al and Ti, with the former stabilizing the lattice oxygen by strong Al–O bonds and the latter improving the Li+ conductivity by expanding the lattice. The facile bulk synergistic doping of LLOs paves avenues toward their application for high‐energy LIBs.